300 WSM vs. 300 WM

Glassin welcome to the Forum. I have a 300 wsm just got it on a good deal. I have nothing to add to your question. But i can tell you that there are alot of helpful people on this forum.. Welcome Again...

Thinking over prospect of getting a 7rm or 300wm in near future so if I read this correctly both are good rounds to choose from but the wm better for longer heavier bullets? 2nd question can the WM be head spaced off of shoulder by bumping shoulder back .002 or does this weaken the brass in this particular round? And is it worth the effort.

Messed that question up. I am thinking of a 7mm but my question was meant to be about the 300wsm and 300wm being both good round but the wm version handles 200gr bullets and heavier better and if the 300wm can be head spaced off of the shoulder by bumping it back .002 and is it worth the extra time??

That is the way you should resize almost any brass, headspace .002 off the shoulder. Forget about the belt.
For what it's worth, after a fair amount of experience with both, I prefer the 7 mag to a .300. It's pretty hard to beat a .284 180 gr Berger with its' .659 G1 BC. Sure you can go to the 210 gr .308 bullet for .631 BC, and no appreciable difference, but the extra 30 grains of bullet and heavier powder load make for stouter recoil. Not much maybe, but stouter.
In the end they are close enough that I don't believe an elk is going to know the difference at any range.
I would go with a .338 and super high BC's if I thought I needed more than what my 7mm delivers.